How this refresh rate test works
No browser feature simply reports your monitor's refresh rate, so the test measures it. Your browser draws a new frame once per screen refresh and tells the page exactly when. The test records the time between frames for 5 seconds, skips the first half second while things settle, sets aside frames that came late, and averages the rest. At 144 Hz that is about 700 frames, which is why the result is steady to a fraction of a hertz even though the browser clock is rounded.
The number is labelled Estimated because it measures the browser's drawing rate. In almost every setup that equals the monitor's rate, but the browser can slow itself down, and the notes under the result tell you when that is likely.
How to read the result
- Refresh rate: the measured rate, with the standard rate it matches (60, 75, 120, 144, 165, 240 Hz and so on). A reading of 143.9 or 59.94 is normal.
- Frame time: how long each frame lasts. 16.7 ms is 60 Hz, 6.9 ms is 144 Hz, 4.2 ms is 240 Hz.
- Dropped: refreshes the browser missed. A handful is fine. Dozens mean the computer was busy during the test.
- Jitter: how much frame times vary. Under 0.5 ms is very steady.
- Histogram: one tall, narrow bar is a healthy result. A second bar at twice the frame time means regular stutter.
Monitor stuck at 60 Hz? Check these in order
- Cable and port. Plug the monitor into the graphics card, not the motherboard, if your PC has both. Use DisplayPort, or an HDMI 2.0 or 2.1 cable and port for high rates. Old HDMI 1.4 cables, adapters and many USB-C docks top out at 60 Hz at high resolutions.
- Windows display settings. Open Settings, System, Display, Advanced display, and pick the highest rate under Choose a refresh rate. Select the right monitor at the top first if you have several. On a Mac, open System Settings, Displays, and set Refresh rate.
- GPU control panel. In NVIDIA Control Panel, open Change resolution and set the refresh rate. In AMD Software, check Display settings. Choose a resolution listed under PC, not TV, as TV modes are often limited to 60 Hz.
- Monitor menu. Some monitors need overclock or high refresh mode switched on, or the right input version (for example DisplayPort 1.4) chosen in the on-screen menu.
- Browser hardware acceleration. In Chrome or Edge open Settings, System, and turn on Use graphics acceleration when available, then restart the browser. Without it, pages can be held to 60 fps.
- Multiple monitors. Some browsers draw at the main monitor's rate everywhere. Move the window to the fast screen and measure again, or make the fast screen your main display.
- Battery saver. On a laptop, plug in the charger and turn off battery saver and the browser's energy saver. Windows 11 Dynamic Refresh Rate can also keep a laptop at 60 Hz until you scroll.
- VRR. G-Sync, FreeSync and Adaptive Sync change the rate in games, but a browser window usually runs at the fixed maximum. A browser test cannot show whether VRR is working; use the GPU panel or the monitor's frame rate counter in a game.
Browser limits worth knowing
Safari draws pages at about 60 fps by default, so a 120 Hz iPhone, iPad or MacBook Pro reads 60 Hz there; Chrome on the same Mac shows 120. Low Power Mode on iPhones caps the screen at 60 Hz. Background tabs pause drawing, so the test pauses and restarts when you come back. For motion clarity, ghosting and overdrive, use the reference motion tests at testufo.com.
More monitor tests
Got a new monitor? Run the dead pixel test, then check backlight bleed on the black screen and uniformity on the white screen.
Questions
How do I check my monitor refresh rate?
Open this page on the monitor you want to check and wait about 5 seconds. The test counts how often your browser draws a new frame and shows the rate in Hz, plus the nearest standard rate such as 60, 144 or 240 Hz.
Why does it say 60 Hz on my 144 Hz monitor?
Usually the monitor is set to 60 Hz in Windows or macOS, the cable or port cannot carry more, or the browser is limiting itself (Safari, battery saver, or a window on a second screen). Work through the checklist on this page in order.
Why does it show 143.9 Hz and not 144 Hz?
Real monitors run a tiny bit off their label, for example 143.86 Hz or 59.94 Hz, and the browser clock adds small rounding. The test shows the measured number and the standard rate it is closest to.
Is a browser refresh rate test accurate?
It is an estimate, but a good one: averaged over hundreds of frames it is usually within a few tenths of a hertz on a quiet computer. It measures how often the browser draws, which matches the monitor in almost every setup. Heavy load, battery saver or a busy tab can pull it down.
Why does my iPhone or MacBook show 60 Hz?
Safari limits web pages to about 60 frames per second by default, even on ProMotion screens, and Low Power Mode caps the screen at 60 Hz. Chrome on a Mac shows the full rate. The screen itself is still capable of 120 Hz.
What are dropped frames?
A dropped frame is a moment when the browser missed a refresh and the same picture stayed on screen twice. A few during the test are normal. Many dropped frames mean the computer is busy, which also causes stutter in games.
Does this test G-Sync or FreeSync?
No. A browser cannot see whether variable refresh rate is active, and a windowed browser usually runs at the fixed maximum rate. Use your GPU control panel or the monitor on-screen display to check VRR.
Should I use TestUFO instead?
For motion blur and ghosting, yes: testufo.com has the reference motion tests. This page focuses on reading your refresh rate quickly and explaining why it might be stuck at 60 Hz.
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